Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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THE LIQUID COMPOSITION FOR PROMOTING PLANT GROWTH, WHICH
INCLUDES NANO-PARTICLE TITANIUM DIOXIDE
Technical Field
The present invention relates to a liquid composition
for promoting plant growth, which contains titanium dioxide
nanoparticles. More particularly, the present invention
relates to a liquid composition for promoting plant growth,
which has a bactericidal action against pathogen, partially
provides nutrients and constituting substances for plants,
and permits increasing the solar energy utilization
efficiency of plants in a plant photosynthesis process,
significantly increasing crop yield.
'
Background Art
Currently, a problem to be solved in an agricultural
field is to minimize land devastation and environmental
contamination caused by over-application of various
chemicals used for the increased production of foods.
Methods for promoting plant growth according to the
prior art can be broadly divided into two ones.
A first method which utilizes chemical fertilizers
temporarily seems to be effective, but ultimately
deteriorates the conditions of the soil on which plants
grow. Thus, a vicious circle arises in that fertilizers
must be applied again in order to improve the deteriorated
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soil conditions. As a result, this method is not preferred
in a long-term view.
A second method utilizes plant growth regulators which
are plant extracts or similar substances which are
artificially synthesized.
A method is known which utilizes N-acylalanine
derivatives, indole acetic acid, gibberellin,
benzylaminopurine, indolebutyric acid, or a mixture thereof.
However, this method is expensive and has a handling
problem in that an alcohol solvent must be used. Also,
this involves limitations causing chemical injury to plants.
Moreover, the use of these substances provide some
growth promoting effects, but shows a side effect and
inevitably involves a damage caused by the improper use of
chemicals. Plants must adapt to the surrounding
circumstance in order to regulate in vivo metabolism of
plants. Nevertheless, the method limited only to the
growth of plants results in a reduction of productivity and
even killing of plants.
Meanwhile, Korean Patent No. 10-0287525 (entitled
"plant growth promoter") discloses a plant growth promoter
which utilizes 2-methyl-4-dimethylaminomethyl-5-
hydroxybenzimidazole, thereby inhibiting mutation,
preventing oxidation and increasing resistance to disease.
The above chemical fertilizer and the plant growth
promoter consist mostly of artificially synthesized organic
substances which have various components. Thus, even when
the same is used, a result varying depending on the
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condition of use is obtained.
Recently, there was an attempt to substitute the
chemical fertilizer with natural inorganic substances
containing composite ingredients. However, this shows an
insufficient effect while it seems that much damage will be
caused by mixed heavy metals.
Meanwhile, there were attempts to develop new agents
for promoting plant growth by using functions of known
substances. However, they showed an insufficient effect, a
reduced economical efficiency and a limited application
range.
Disclosure of Invention
The present invention relates to a liquid composition
for promoting plant growth, which contains titanium dioxide
nanoparticles. The present invention comprises finding new
substances which promotes growth and metabolism of plants
and at the same time, not causes a problem of environmental
contamination. In addition, it comprises conducting an
optimized application test for plants.
Factors necessary for plant growth include nutrient,
moisture, temperature, light and the like. Plant growth
when other conditions are the same is determined by the
amount of the most deficient inorganic element according to
the law of minimum nutrient. Although optimizing a feed
rate of inorganic elements for each of various plants is
necessary, but it is actually difficult since soil or the
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surrounding environmental conditions for growing plants
vary.
Therefore, deviating from the conventional formality
of combinations of organic fertilizers with inorganic
elements, the present inventors have made an attempt to
find a new substance which has been not used hitherto.
On the basis of the fact that plants grow while
obtaining the nutrients from the substances synthesized by
photosynthesis based on solar energy, the present inventors
have attempted to find the substances capable of utilizing
solar energy.
As a substance consistent with the above object, the
present inventors have found photocatalytic titanium
dioxide (TiO~), which has a guaranteed safety for a human
body and plants, and functionalities including
sterilization and decomposition of poisonous organisms, and
is formed of easily available materials.
By photocatalyst, it is meant to be a substance which
helps chemical reaction to occur by absorbing light of a
necessary wavelength range from sunlight or artificial
illumination.
Such a photocatalytic substance has a function of
oxidizing the poisonous substances into carbon dioxide
( COa ) and water ( HBO ) using oxygen ( OZ ) and water ( HZO ) as
oxidants under light irradiation.
As photocatalyst, titanium dioxide is recently
highlighted, which is relatively inexpensive, not
photodecomposed, can be used in a semi-permanent manner and
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does not cause a problem of environmental contamination.
Also, in advanced industrial nations including Japan,
Europe and America, titanium dioxide was applied in home
and industrial sections for antibiosis, deodorization, air
cleaning and like, and is increasingly enlarged with
respect to its use.
Based on this point, the present inventors have first
discovered a manner of applying photocatalytic titanium
dioxide directly to plants.
The titanium dioxide nanoparticles according to the
present invention were prepared in such a manner that it is
readily available to plants in a colloidal state, whereas
prior inorganic fertilizers including lime and siliceous
fertilizers are not readily available to plants since they
are in a solid state.
It is known that the prior lime or siliceous
fertilizers, etc., are mostly transferred through soil,
slowly solubilized by organic acids in soil or acids
secreted from crop roots, and then available to plants by
absorption.
However, the above inorganic fertilizers have a
shortcoming in that their active ingredients are hardly
soluble in water, and form complexes with aluminum (Al) and
iron (Fe), etc., as microelements in soil, so that the
absorption efficiency by crops is lowered.
In order to solve this problem, since fertilizers need
to be applied in an amount larger than an amount available
to plants and a overnutrition state is ultimately caused,
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plants may be disadvantageously grown in a non-normal
manner.
In the present invention, a method of applying
titanium dioxide as a main component directly to the
foliages of crops is used so that an absorption pathway to
crops is expanded to soil and foliages.
Titanium dioxide can be divided into three types
consisting of anatase, rutile and brookite according to its
crystal lattice structure, and has a feature in that its
catalytic activity highly varies depending on the
respective crystal structures.
Among these structures, the rutile structure has weak
photocatalytic activity and thus is used for an assistant
purpose including UV blocking. The anatase and brookite
structures are known to have relatively high catalytic
activity, but their functions are found to be infinitely
varying according to preparation methods.
Furthermore, the photocatalytic activity is closely
connected with the crystal structure and also with the
particle size and specific surface area of titanium dioxide.
Generally, it is known that, as the particle size is
decreased, the specific surface area is increased and the
number of contact point for activity is increased so that
the ability of titanium dioxide to decompose organisms and
serve as catalysts are more excellent.
Currently, commercially available photocatalysts are
mostly used in a state where photocatalyst powders are
suspended in a solution, and in a state where a sol
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solution of titanium dioxide is supported on or into a
carrier.
Typical methods for preparing the photocatalyst
powders include a method where inorganic titanium salt,
such as titanium chloride or titanium sulfate, is
hydrolyzed, neutralized with a base, mixed with a water
soluble metal slat at a given weight ratio and calcined at
high temperature. Also, a sol-gel method using organic
titanium precursor is included.
Among these methods, the sol-gel method utilizes
organic titanium alkoxide as a starting material, so that
it allows a particle size to be uniform and a crystal
structure to be adjusted according to reaction conditions
in a smooth manner, as compared to other methods. For this
reason, the sol-gel method is typically preferred.
In the present invention, titanium dioxide of all
varieties as described above may be used.
Using titanium alkoxid as a starting material, the
titanium dioxide nanoparticles of a particle size ranging
from 3 to 200 nm was crystallized to obtain an anatase-type
structure as a stable dispersion. Test results for the
catalytic activity of the obtained dispersion indicated
that the dispersion was completely comparable with
commercially available titanium dioxide sol solutions, and
the use of the dispersion could provide a more excellent
growth promoting effect.
Where the anatase-type titanium dioxide dispersion
obtained as described above is diluted with water to a
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suitable titanium dioxide concentration, mixed with
methylene blue as organic pigment, and then left to stand
under sunlight, an organic decomposition process of the
photocatalyst can be visually observed. Where plant
pathogens are present in the dispersion and approach to the
surface of the photocatalyst, they can be decomposed by the
action of a hydroxy radical, in the same manner as the
pigment.
However, functions of the photocatalyst in water are
obviously different from function of the photocatalyst
applied to crops. The present inventors have made an
attempt to apply the titanium dioxide photocatalyst to
plants by solving the following technical problems.
First, after recording a concentration of titanium
dioxide diluted with water, there was made an attempt to
determine a minimum concentration at which the
decomposition of organisms can occur.
The present inventors have observed the activity of
titanium dioxide in water. Results indicate that, as the
concentration of the titanium dioxide in water is decreased,
the activity is reduced and then little or no activity
exhibits.
As a result, it was found that the activity exhibits
even at a concentration of less than 10 ppm. This suggests
that titanium dioxide at this low concentration can
sufficiently exploit its functions without causing damage
to the intracellular mechanism, such as a chloroplast,
which is the center of plant photosynthesis, and also
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titanium dioxide can be used in an agricultural section at
relatively low costs.
Second, if nanoparticle titanium dioxide diluted with
water is applied to crops, water will be evaporated with
the passage of time and the portion of unabsorbed titanium
dioxide will remain on the surface of crops as solids. The
existing substances when completely absorbed to plants
exhibit its functions, but titanium dioxide was found to
make plants resistant to external stress by the portion of
titanium dioxide unabsorbed by plants and also to have
positive effects in that it shows a bactericidal and
defensive effects against various phytopathogens.
Third, since titanium dioxide has an isoelectric point
of about pH 4 which but varies according to circumstances,
it maintains a stable colloidal form at the acidic and
alkaline ranges. If the titanium dioxide nanoparticles are
diluted with water, they then gradually approach to the
isoelectric point with an increase in dilution times and
are ultimately changed into the form of precipitates. The
present inventors have found that the effect of titanium
dioxide was highly increased when it was applied to
foliages after its pH was adjusted such that titanium
dioxide could be not precipitated within at least two hours
after dilution.
Moreover, it was found that, as the particle size was
decreased during a procedure of preparing the titanium
dioxide nanoparticle, the precipitating time was delayed.
From the above results, the photocatalytic titanium
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dioxide nanoparticle was found to be suitable as a main
component of the plant growth and metabolism promoting
composition that is the object of the present invention.
It was found that, when the titanium dioxide
nanoparticle after diluted with water was applied to crops,
it promoted the growth of crops and also exhibited a
bactericidal action against phytopathogens. In addition,
some of the titanium dioxide particles provide nutrients
and constituent substances for plants and it increases the
efficiency of solar energy utilization of plants in a
photosynthesis process of plants, thereby significantly
increasing crop yield. Based on these points, the present
invention was achieved.
The liquid composition for promoting plant growth
which contains the titanium dioxide nanoparticles according
to the present invention is formed as follows.
In the composition for promoting plant growth
containing nanoparticle titanium dioxide, a main component
of the composition is an aqueous solution containing
colloidal titanium dioxide, and titanium dioxide has such a
particle size that it can be readily absorbed to plants.
Also, in order to prevent the rapid precipitation of
titanium dioxide in the aqueous solution, a pH of the
solution is adjusted. Moreover, the solution is diluted
with water such that titanium dioxide is adjusted to a
desired concentration. In addition, adjuvants necessary
for plant growth are added and a surfactant for dispersion
is added.
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The present inventors have selected a photocatalytic
titanium dioxide nanoparticle solution as a material for
promoting growth and metabolism of plants, and discovered a
manner capable of simply utilizing the solution by diluting
it with water in order to allow it to be usefully available
to plants.
The titanium dioxide solution has an anatase-type
structure, which is commercially readily available and has
a relatively high photocatalytic activity and a particle
size ranging from 3 to 200 nm.
When the titanium dioxide nanoparticles are diluted
with water and applied to plants, a portion of the
nanoparticles are then absorbed to plants so as to promote
the internal photosynthetic mechanism and metabolism of
plants. The remaining portion of titanium dioxide which
was not absorbed by plants remains on the surface of plants
so that it serves to increase resistance of plants against
various stresses and pathogens.
For the above object, a variety of titanium dioxide
nanoparticles can be used. Although the nanoparticles of a
particle size of 3 to 200 nm have excellent absorption and
workability and shows an excellent increase in crop yield,
a solution in which fine particles of several tens of
microns are dispersed may also be used.
As long as titanium dioxide particles can stably
maintain a dispersed state, any titanium dioxide particles
may be used whether it is primary particles in a
monodispersed state or secondary particles formed by
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aggregation of the primary particles, as observed with a
scanning electron microscope.
Moreover, although the particles of various shapes may
be used, it is preferred for the present invention to use
the sphere-, needle- or plate-shaped titanium dioxide
nanoparticles.
Meanwhile, although the crystal structure of titanium
dioxide used for the above purpose may be anatase-type,
rutile-type, brookite-type or a mixture thereof, the
anatase-type crystal structure is particularly preferred.
The anatase-type crystal structure is excited by
absorbing light of a near-ultraviolet region of about 380nm
wavelengths from sunlight, and at the same time, exhibits
strong oxidation power by separation of electrons from
holes such that it decomposes most of poisonous organisms.
For this reason, it is believed to be a crystal structure
which is most consistent with the above object.
When the colloidal titanium dioxide is diluted with
water and applied to crops, the number of its diluted times
will have a great effect on crop yield.
In the present invention, the concentration of
titanium dioxide nanoparticles after final dilution is 1 to
1,000 ppm, preferably 3 to 300 ppm and more preferably 3 to
150 ppm.
If the concentration is above 1,000, economic costs
will be increased while a possibility of chemical injury
will be rather increased. If the concentration is below 1
ppm, the effect of the titanium dioxide nanoparticles will
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be rapidly reduced.
Since the titanium dioxide dilution when applied to
the foliage of crops shows the highest increase in crop
yield, it basically differs from the existing soil
conditioners.
Since the titanium dioxide nanoparticle which is the
main component of the composition according to the present
invention acts to highly increase the crop yield by itself,
it shows a sufficient growth promoting effect without
mixing with separate assistant additives. However, it is
obvious to those skilled in the art that fertilizer
ingredients necessary for the growth of plants, other
metallic or non-metallic oxides, or surfactants used as an
absorber or a spreader, may be added.
Oxides Of Li, Be, B, Na, Mg, Al, Si, P, K, Ca, Sc, V,
Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, Se, Zr or a mixture
thereof may be used as the fertilizer ingredients or
metallic or non-metallic oxides. Furthermore, as long as
the materials containing the above elements are dissolved
in water and can be absorbed by plants, carbonates,
chlorides, nitrates or sulfates of the above elements may
also be used.
The amount of adding of the metallic or non-metallic
oxides are 0.1 to 20% by weight, and preferably 0.5 to 15%
by weight, relative to the titanium dioxide solids that are
the main components of the liquid composition according to
the present invention.
A bactericidal effect shown by the titanium dioxide
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nanoparticle solution is due to the oxidation strength of
semiconductor which causes when illuminating directly or
indirectly sunlight. For this reason, under the condition
having the blocking of sunlight or the nighttime having
little or no radiation of sunlight, the bactericidal effect
will be deteriorated.
Based on this point, the present inventors have found
that silver (Ag) nanoparticles having the ability to make
phytopathogens extinct by contacting with the
phytopathogens can be used as another adjuvant.
Generally, the silver nanoparticles having a particle
size of 1 to 100 nm are stably dispersed in an aqueous
solution. If the silver nanoparticles after added to the
titanium dioxide solution is applied, the ability of the
titanium dioxide is then further increased due to high
bactericidal activity of the silver nanoparticles.
Moreover, the silver nanoparticle which is an expensive
substance is difficult to apply to agricultural crops alone,
but when mixed with the nanoparticle titanium dioxide, it
exhibits excellent bactericidal activity only at the
minimum quantity.
Although the amount of adding of the silver
nanoparticles may be selected within a range at which
economical efficiency is ensured, the present inventors
have found that it is preferably in the range of 0.5 to 20%
by weight, and more preferably 1.0 to 10% by weight,
relative to the titanium dioxide solids.
In the present invention, the surfactant which may be
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added to the aqueous titanium dioxide solution and used as
an absorber or spreader includes a cationic surfactant, a
nonionic surfactant, an anionic surfactant, and an
ampotheric surfactant. The kind of surfactant used varies
depending on the kind of plants to which the titanium
dioxide solution is added.
One or two kinds or more of the surfactants as
described above are mixed at a suitable ratio and added to
the aqueous titanium dioxide solution. In this case, the
amount of adding of the surfactants is preferably 0.1 to 5%
by weight, and more preferably 0.2 to 1% by weight,
relative to the titanium dioxide solids.
Brief Description of the Drawings
FIG. 1 is a graph showing the culm growth effect of a
rice plant treated with the liquid composition for
promoting plant growth according to the present invention.
Best Mode for Carrying Out the Invention
The present invention will hereinafter be described in
further detail by examples. It should however be borne in
mind that the present invention is not limited to or by the
examples.
EXAMPLE 1: Preparation of liquid composition for
promoting plant growth containing titanium dioxide
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In this example, a liquid composition for promoting
plant growth is prepared using titanium dioxide
nanoparticles.
This composition is characterized in that it contains
the titanium dioxide nanoparticles of 3 to 200 nm.
As organic titanium alkoxide which is a starting
material of titanium dioxide according to the present
invention, TTIP (Titanium-Tetraisopropoxide, JUNSEI, 97%)
was used.
240 ml of 70o nitric acid was 8.94 liters of deionized
water.
To this solution, 720 ml of TTIP was added dropwise.
The mixture was stirred under reflux at 80 °C to be
hydrolyzed.
At the reaction was terminated, a blue titanium
dioxide colloidal solution was obtained. Titanium dioxide
solids: 2.0%, pH = 7Ø
The crystal structure of the titanium dioxide colloids
was found to be an anatase-type as observed with XRD. Also,
more than 950 of the titanium dioxide nanoparticles were
present in the particle size range of 15 to 25 nm.
300 ml of 70% nitric acid was added to the titanium
dioxide colloidal solution so that the solution was
adjusted to pH 0.5.
To this solution, 7990 liters of water was added so
that the concentration of titanium dioxide became 25 ppm.
This solution (sample A) was used as an application
solution to plants.
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Application Test
The sample A obtained in Example 1 was provided as an
solution to be applied to plants, and rice and corn plants
were selected as objects to be applied with the sample A.
In the case of the rice plants, in order to examine a
change in crop yield according to an environmental change,
those grown on a PET vessel in a laboratory were compared
to those grown directly on open fields.
Also, the sample was applied to individuals whose
tillering had been completed, such that the effect of a
difference between tillers on crop yield could be
eliminated.
In order to verify the plant growth promoting effect
of the titanium dioxide nanoparticles which were applied to
the respective crops, the rice plants were recorded for
their culm length, weight, grain weight and thousand grain
weight(i.e., weight per thousand kernels), and the corn
plants were recorded for the weight of individuals after
harvesting.
In order to verify the bactericidal and defensive
abilities of the titanium dioxide nanoparticles contained
in the sample A, two species of phytopathogens were
selected and tested according to a screening method
provided by Korea Research Institute of Chemical Technology.
Test Example 1: Test of effect of composition
according to Example 1 in rice plants
Rice plants whose tillering had been completed under
the same condition were planted on a PET vessel, and
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solutions after divided into a sample A and a control were
applied to the rice plants and examined for their effect.
Table 1: Results measured for weight of rice plants
grown in PET vessel and for grain weight
Total weight Weight increaseTotal weightYield crop
of of
rice relative grain increase
to
plant(average,control (%) (average, relative
g) g) to
control
(%)
Sample 119.1 21.6 19.2 44.4
A
Control 97.9 0.0 13.3 0.0
In Table 1, the sample A where the titanium dioxide
solution prepared by the sol-gel method described in
Example 1 was diluted and applied to plants exhibits a more
than 20o increase in weight as compared to the control, due
to the growth promoting effect of the titanium dioxide
nanoparticles. Particularly, the total weight of grains
was increased by more than 40 o as compared to the control.
This suggests that an increase in crop yield of the sample
A as compared to that of the control is significant.
Test Example 2: Test of effect of composition
according to Example 1 in rice plants
Rice plants whose tillering had been completed were
planted on the open fields, and solutions after divided
into a sample A and a control were applied to the rice
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plants and examined for their effect.
FIG. 1 indicates that when the titanium dioxide
solution (sample A) was applied, the culm length was
increased by about 13% as compared to the control. In the
state of the rice plants at harvesting, the sample A
exhibited good erectness and light interception, similarly
to the control, and thus it showed little or no lodging.
Table 2: Results measured for weight of rice plants
grown in open field and for grain weight
Total weight Weight increaseTotal weightYield crop
of of
rice relative grain increase
to
plant(average,control (%) (average, relative
g) g) to
control
(%)
Sample 145.06 39.9 205.2 31.8
A
Control 103.66 0.0 155.7 0.0
Table 2 indicates that when the titanium dioxide
solution was applied on an open field, crop yield was
increased by more than 30%, as in the case of the PET
vessel.
Table 3: Results measured for hull ratio and thousand
grain weight in rice grown on open field
Thousand grain weightRatio of hull in
(g) grain
Sample A 24.22 17.2
Control 24.38 17.9
Table 3 shows thousand grain weight and hull ratio in
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the grains which were harvested on an open field in order
to analyze a crop yield-increasing effect of the titanium
dioxide solution. The sample A exhibited the thousand
grain weight and the hull ratio in grains which are similar
to those of the control. This suggests that crop yield was
increased due to an increase in the number of grains other
than an increase in grain weight.
Also, FIG. 1 shows a 13% increase in culm length, and
Table 2 shows a 31.80 increase in grain weight. This
indicates that when the titanium dioxide-containing
solution was applied, not only the length was increased but
also the metabolism was promoted such that the grains could
be yielded at a larger amount.
Test Example 3: Test of composition of Example 1 on
corn ~alants
The sample A and the control were separately applied
to feed corn plants grown on an open field, and examined
for their effect.
Table 4: Result measured for weight and increase in
yield of corn plants
Total weight of cornIncrease in yield
plants relative
(average, g) to control
Sample A 3,670 46.1
Control 2,511 0.0
Table 4 indicates that when the titanium dioxide
nanoparticles were applied to feed corn plants as field
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crops, crop yield could be increased by more than 400.
These results verify the growth promoting effect and
metabolism promoting effect of the titanium dioxide
nanoparticles, although these results can somewhat vary
since only the weight of the harvested corn plants is
measured.
Test Example 4: Bactericidal Test
In order to verify the bactericidal activity and
defensive ability against phytopathogens of the titanium
dioxide nanoparticles used in a foliar application solution
according to the present invention, a test was carried out
according to a screening method provided by Korea Research
Institute of Chemical Technology.
In the test, Pyricularia oryzae (RCB) and Botrytis
cinerea (TGM) were used as the phytopathogens, and a
primary screening method was conducted as follows.
For rice blast, a Magnaporthe grisea KJ201 cell line
as a pathogen was first inoculated to a rice bran agar
medium (Rice Polish 20g, Dextrose lOg, Agar 15g, distilled
water 1L ) and cultivated in an incubator at 25 °C for two
weeks.
The surface of the medium in which the pathogen had
been grown was scratched with Rubber Polishman to remove
aerial hypha. The medium was left to stand on a shelf at
25-28 °C for 48 hours under fluorescent light to form
spores. In inoculating with pathogen, conidia were
suspended in sterile distilled water to a conidium
suspension of a concentration of 106 conidia/ml which was
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then sufficiently sprayed on rice plants (2-3 normal leaf
stage) treated with chemicals, such that it could be
dropped down.
The inoculated rice plants was left to stand on a
moist-chamber in a dark state for 24 hours, after which
they were diseased in a constant temperature and moisture
chamber at a relative humidity of more than 80% and 26°C
for 7 days and examined for infected leaf area.
Meanwhile, for tomato gray mold, Botrytis cinerea as a
pathogen was inoculated to a potato agar medium, cultured
in an incubator at 25 °C for 7 days, and further cultured
for 7 days while maintaining a 12 hours light/12 hours dark
cycle every day, thereby forming spores.
In inoculating with disease, the conidia formed in the
medium were collected as potato dextrose broth, and treated
with a hemacytometer so as to have a conidium concentration
of 106 conidia/ml. Then, they were inoculated to young
tomato plants (2-3 leaf stage) treated with chemicals. The
inoculated tomato plants were decreased on a moist chamber
at a relative humidity of more than 95% and at 20°C for 3
days, and examined for infected leaf area.
In treating with the titanium dioxide solution, the
solution was diluted with water to a titanium dioxide
concentration of 100 ppm. Four solutions divided into two
for each of diseases were disposed on a table and applied
to plants with a spray gun (1 kg/cm2) with rotation such
that they could be uniformly attached to the entire plants.
Then, the plants were grown on a greenhouse and inoculated
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with pathogens.
Table 5: Result measured for protective value for rice
blast and tomato gray molding
I~SC No. Titanium Protective value
(%)
concentration Rice blast (RCB) Tomato gray
(ppm) mold
(TGM)
47314 100 78 17
The titanium dioxide solution applied as described
above exhibited high bactericidal activity against rice
blast, and also showed weak bactericidal activity against
tomato gray mold.
15 Table 6: Comparison of protective value of Titanium
dioxide solution with general bactericidal agent
Plant disease Control agentsConcentration Protective
(ppm) value
(%)
Rice blast (RCB)Blasticidin-S 50 100
1 70
Tomato gray Fludioxonil 50 100
mold
5 56
Table 6 shows the bactericidal activity and use
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concentration of control agents used as a bactericidal
agent. The titanium dioxide solution of the present
invention exhibits bactericidal activity regardless of the
kind of pathogens, although it shows a decreased
bactericidal activity as compared to the control agents.
If plants were not yet attacked with pathogens, the
titanium dioxide solution has an advantage in that the
portion of titanium dioxide nanoparticles remaining on the
plants serves to inhibit the generation of lesion.
Particularly, the titanium dioxide solution is advantageous
in that it is harmless to organisms.
Namely, the titanium dioxide nanoparticles are applied
to plants, they exhibit an effect of promoting plant growth
and metabolism while showing bactericidal and defensive
activities against plants. Therefore, the plants applied
with the titanium dioxide nanoparticles becomes strong
against disease and insect pest and also exhibits excellent
adaptability to a change in surrounding environment,
thereby increasing crop yield.
Industrial Applicability
As described above, the present invention provides the
liquid composition containing the titanium dioxide
nanoparticles as a main component.
Where the plant growth promoting composition is
applied to plants, a portion of titanium dioxide absorbed
by the plants then serves to promote the internal
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CA 02471605 2004-06-23
WO 03/059070 PCT/KR02/02142
photosynthetic mechanism and metabolism of the plants,
while an unabsorbed portion of titanium dioxide remains on
the surface of the plants so that it acts to increase
resistance of the plants to various pathogens which can be
flowed in from the outside. Particularly, the titanium
dioxide nanoparticles exhibit bactericidal activity
regardless of the kind of pathogens and thus can be used in
a wide applicable range.
